EPICYCLIC CHANGE SPEED GEAR HUBS

Abstract: An epicyclic bicycle change speed gear hub comprises primary and secondary sun pinions (12) and (13) disposed side-by-side on the spindle (14) of the hub. A split selector key (11) comprising first and second parts (15 and 16) is mounted on a support rod (17) for relative movement axially of the hub. Dogs (19 and 21) on respective parts (15 and 16) can be brought into selective cooperative engagement with splines (31 and 32) inwardly of the sun pinions (12 and 13) to lock the selected pinion to the spindle (14) in drive transmission mode. The selector key (11) is movable axially into abutment with a selector sleeve to effect axial adjustment thereof against the restraint of a return spring to provide for change between high and low gears thus providing a compact arrangement.

Description: EPICYCLIC CHANGE SPEED GEAR HUBS The invention concerns epicyclic change speed gear hubs for bicycles and the like, and has more particular reference to hubs having two or more sun gears selectively engageable with respective gear elements of compound planet gears in a drive transmission mode. It is known in the art to provide a five speed epicyclic change speed gear hub for a bicycle by utilising compound planet gears engaged with a common gear ring and each cooperable with a respective sun gear selectively engageable therewith in a drive transmission mode. In such an arrangement the sun gears are rotatably and slidably mounted on the hub spindle for unitary movement in the axial direction thereof for the selective dogged engagement of one or other of the sun gears with a respective formation non-rotatably fixed to the spindle. The planet cage of the aforesaid arrangement is connectable with the hub shell, so as to provide a drive transmission from the planet cage to the hub shell according to hub condition, by means of axially movable pawls mounted in the planet cage and cooperable with ratchet teeth provided in a hub end cap. The gear ring is connectable with the hub shell through radial pawls. It is also known from our copending Patent Application No. GB-A-2249364 for a sun gear to be axially fixed with respect to the spindle and to provide a selector key movable axially of the spindle for selective engagement with a respective one of the sun gears so as non-rotatably to secure that sun gear to the spindle-. The object of the present invention is to provide an alternative means whereby the respective sun gears might selectively -be brought into a drive transmission mode, and preferably one such as will allow of the use of a single cable in effecting gear change through the full range of available gears. According to the present invention there is , , . le or like epicyclic change speed gear having side-by-side sun pinions freely rotatable on a common spindle and a gear selector key disposed radially inwardly of said sun pinions and adapted for selective cooperative engagement with one or other of the said sun pinions on movement of the selector key in the axial direction of the hub, the selector key including a support rod, first and second body parts mounted on said rod for limited relative movement in the axial direction thereof, and resilient means resisting said relative movement. According to a preferred feature, each body part includes an outward extending dog for cooperative engagement with splines provided internally of the sun pinions. According to a still further preferred feature, the sun pinions are resiliently loaded into abutting side-by-side disposition. According to a still further preferred feature, the gear selector key is movable into axial abutment with a selector sleeve of the epicyclic change speed hub to effect axial displacement thereof. According to another aspect of the invention, a clutch sleeve is provided internally of the selector sleeve and between the selector sleeve and hub spindle, the clutch sleeve being movable axially relative to the selector sleeve and there being resilient means between opposed formations on the clutch sleeve and selector sleeve, respectively, resisting movement of the clutch sleeve relative to the selector sleeve outwardly of the hub and the selector key displacing the selector sleeve outwardly of the hub through said resilient means. According to a preferred feature the clutch sleeve has a radially outwardly directed lip at its inner end and the selector sleeve has an internal rib, the lip being an interference fit with said rib, and the resilient means comprising a helical compression spring interposed therebetween. The invention will now be described further, by way of example only, with reference to the accompanying drawings in which : - Fig. 1 is an exploded perspective view of the split selector key of the present invention and a hub spindle; Fig. 2 shows a section through the selector key of Pig. 1 in position relative to the sun pinions and planet gears of a coaster change speed hub, and in a particular gear condition of the hub, and illustrates the manner in which the key serves to lock one of the sun pinions in r drive transmission relationship with respect to the hub spindle; Fig. 3 is an axial section through a five speed bicycle epicyclic change speed hub including the selector key shown in Figs 1 and 2, the relative disposition of parts being consistent with a super high gear condition of the hub; Figs 4 to 7 are views similar to Fig. 1 and show the relative disposition of parts appropriate to the successive gear conditions of the hub between high gear and super low gear. Referring now to the drawings, and particularly to Figs. 1 and 2 thereof, a split selector key 11, whereby primary and secondary sun pinions 12, 13, freely rotatably arranged in side-by-side disposition on the spindle 14 of a bicycle change speed hub, are selectively locked in relation to that spindle, comprises first and second rectangular body parts 15, 16 arranged in abutting relationship and mounted on a support rod 17 for relative movement in the axial direction thereof. Integral dogs 19, 21 are provided at the upper face, as seen in the drawing, of body parts 15, 16 the dogs 19, 21 being at the remote ends of said body parts and the inwardly facing surfaces thereof being bevelled as at 22. Aligned through bores 23, 24 are provided in body parts 15, 16 respectively, bore 23 being clearance on rod 17 whilst bore 24 is of lesser diameter and is screw-threaded to receive a complementarily threaded reduced diameter end region 25 of rod 17. The opposite end of rod 17 has an enlarged head 26, and a helical compression spring 27 is provided about rod 17 and between the head 26 and the adjacent face 28 of body part 15. As will be appreciated, in the assembled condition of the selector key 11, body part 15 will be capable of limited movement on rod 17 relative to body part 16 against the restraint of spring 27 and will ordinarily be loaded into face-to-face abutment with body part 16 by said spring. The split selector key 11 is located in a slot 29 in hub spindle 14 at a position radially inwardly of side-by-side primary and secondary sun pinions 12, 13 and, by providing for movement of said key 11 in the axial direction of the spindle, the dogs 19, 21 can be brought into selective cooperative engagement with splines 31, 32 inwardly of sun pinions 12, 13 respectively, thereby to lock the selected sun pinion to the spindle 14 in drive transmission mode. Referring now to Figs. 3 to 7, in which like numerals to those of Figs. 1 and 2 are used for the same or similar parts, the five speed epicyclic change speed hub shown therein comprises primary and secondary sun gears 12, 13 freely rotatable on spindle 14 and essentially axially located with respect thereto. The sun gears 12, 13 are in driving engagement with respective gear elements 33, 34 of compound planet gears 35, only one of which is shown, rotatably mounted in a planet cage 36, whilst the compound gears 35 are drivingly engaged with a gear ring 37. Unidirectional clutches 38, 39 are provided between the planet cage 36 and hub shell 41 and between the gear ring 37 and hub shell 41, and a manually actuable selector mechanism is provided to determine the drive transmission path from an input sprocket to and through the operative epicyclic gear. The hub illustrated includes a cable actuated hub brake, but such brake is of conventional construction and forms no part of the present invention. The manually actuable selector mechanism comprises a selector sleeve 42 and the selector key 11. Selector sleeve 42 receives an input drive from chain sprocket 43 and transmits such drive to planet cage 36 according to the axial position of the selector sleeve within the hub, and serves also to control the operative condition of various of the unidirectional clutches, all in known manner. Selector key 11 is located in elongate slot 29 in hub spindle 14, there being a blind axial bore 44 in said spindle 14 extending to and beyond the said slot, the bore 44 being clearance on a control rod 45, the end of which is screw-threadedly engaged with the outer end of bore 24 in body part 16, by which the key 11 is axially adjusted for gear change. That part 44a of bore 44 which extends beyond the slot 29 is clearance on and of sufficient length to accommodate that part of support rod 17 which extends from the body parts 15, 16.; In addition to selectively securing one or other of the sun gears 12, 13 in non-rotatable relationship to the spindle 14 according to its axial position relative thereto, selector key 11 also effects axial adjustment of selector sleeve 42, the outer end of body part 16 being engageable with bore 46 to the selector sleeve 42 to bear against an internal flange 56 therein in a manner hereinafter to be described, and thus effect axial adjustment of said sleeve 42 against the restraint of a return spring 47. As is shown in the drawing, primary sun pinion 12 abuts against a rib 48 on the spindle 14 and is resiliently loaded against said rib by a compression spring 49 acting on secondary sun pinion 13 through a cup 51, the sun pinions thus being capable of limited movement against the restraint of spring 49. In contradistinction to conventional practice, wherein a clutch nut extending through the hub spindle makes direct contact with the selector sleeve to move said sleeve against spring restraint on gear change in one direction, in the present instance axial displacement of the selector sleeve 42 against the restraint of return spring 47 is through a lipped clutch sleeve 53 provided between the selector sleeve 42 and hub spindle 14, the lipped end of clutch sleeve 53 bearing against the element by which the selector sleeve is axially displaced for gear control purposes, in this case the selector key 11, and there being a compression spring 54 between lip 55 and an internal flange 56 to the selector sleeve. A washer 57 is provided about the spindle at the opposite end of the clutch sleeve 53 and bears against the annular end face thereof, the washer 57 being dimensioned for engagement with the outer flank of rib 56 and spring 52 acting on such washer in loading the selector sleeve 47 inwardly of the hub. By providing the arrangement comprising clutch sleeve 53 and spring 54 between the selector key 11 and the selector sleeve 42 and effecting adjustment of the selector sleeve through the clutch sleeve and related spring we have been able to reduce the space requirement within the hub, the arrangement allowing of a reduction in the extent of axial movement of the selector sleeve 42 as the selector key 11 moves to bring dog 19 on body part 15 out of engagement with secondary sun pinion 13 and into engagement with primary sun pinion 12 in shifting between low gear and super low gear than would otherwise be the case. The facility of limited relative axial movement between the sun pinions 12, 13 provided by spring 49 and cup 51 and between the body parts 15, 16 as provided by spring 27 makes possible the temporary separation of the pinions 12, 13 or body parts 15, 16 on gear change in the event of misalignment between the dogs 19, 21 with the splines provided internally of the relevant gear until such time as accurate alignment occurs and engagement can take place. The relative disposition of parts for the individual gear conditions of the hub are shown in Figs. 3 to 7, Figs 3 and 7 showing the super high and super low gears, respectively, for which the primary sun pinion 12 is locked to the hub spindle 14 and Figs. 4, 5 and 6 showing the hub in high, normal and low gear condition respectively for which the secondary sun pinion 13 is locked to the hub spindle 14 and is in drive transmission mode. Movement of the selector key axially of the hub is effected through control rod 45 in conventional manner, and progressive movement of the selector key to the right from the position shown in Fig. 3 to that shown in Fig. 7 by appropriate increments will adjust the hub successively from super high gear to super low gear. In Figs 3 and 4 it will be noted that the sun pinions have been pushed inwardly of the hub by the selector sleeve, whilst in the remaining gears the pinions are located against rib 48 on spindle 14 by compression spring 49. In adjustment from the super high gear condition of Fig. 3 to the high gear condition of Fig. 4, dog 21 on body part 16 moves out of engagement with the splines of the primary sun pinion 12 whilst dog 19 on body part 15 engages the splines of secondary sun pinion 13, there being no axial adjustment of the selector sleeve 42 and such selector sleeve being drivingly engaged with planet pins 58 thus to rotate planet cage 36, in both gear conditions, the drive transmission path being from the planet cage 36 to the gear ring 37 and thence to the hub shell 41 through unidirectional clutch 39, the gear ratio being determined according to the sun pinion secured in a drive transmission mode. Further adjustment of the selector key to the right, as seen in the drawings will move the selector sleeve 42 out of operative engagement with the planet pins 58, and will give a direct drive to the hub shell from driver 61 through pawls 62, gear ring 37 and unidirectional clutch 39. At the same time the sun pinions 12, 13 move into abutment with rib 48 under the effect of spring 49 operating through cup 51, to ensure extra engagement of dog 19 with secondary sun pinion 13 in low gear. A still further adjustment of the selector key 11 moves the selector sleeve 42 to a position wherein the pawls of unidirectional clutch 39 are tripped, and the drive transmission path is to the gear ring 37 through the epicyclic gear to the hub shell by way of unidirectional clutch 38. The dog 19 on body part 15 is still engaged with the splines provided internally of the secondary sun pinion 13, and such pinion forms a part of the effective epicyclic gear. On still further movement of the selector key dog 19 is disengaged from the secondary sun pinion 13 and dog 19 is brought into engagement with the primary sun pinion 12 which then becomes a part of the effective epicyclic gear, the drive transmission path again being to the gear ring 37, through the epicyclic gear to unidirectional clutch 38 and thence to the hub shell. The invention is not restricted to the detail of the embodiment hereinbefore described, since alternatives will readily present themselves to one skilled in the art. Thus, for example, whilst it is preferred to provide a resiliently loaded clutch sleeve through which motion of the selector key is transmitted to the selector sleeve, the inclusion of such an arrangement is by no means essential. Its inclusion, however, does offer the advantage of a reduced space requirement within the hub, and this is of significance in hub design where economies of space are of paramount importance. The spring loading of the sun opinions may be omitted, if desired, although the provision of such feature does facilitate gear change in circumstances where initial engagement with the splines of a sun gear is involved. Whilst the invention is of application to change speed gear hubs having integral brakes, and is indeed illustrated in the context of one such hub, it does, of course, have application in hubs which do not incorporate a brake.

Claims: CLAIMS 1. An epicyclic change speed gear having side-by-side sun pinions freely rotatable on a common spindle and a gear selector key disposed radially inwardly of said sun pinions and adapted for selective cooperative engagement with one or other of the said sun pinions on movement of the selector key in the axial direction of the hub, the selector key including a support rod, first and second body parts mounted on said rod for limited relative movement in the axial direction thereof, and resilient means resisting said relative movement. 2. An epicyclic change speed gear as claimed in claim 1, in which each body part includes an outward extending dog for cooperative engagement with splines provided internally of the sun pinions. 3. An epicyclic change speed gear as claimed in claim 1 or 2, in which the sun pinions are axially movable and are resiliently loaded into abutting side-by-side disposition. 4. An epicyclic change speed gear as claimed in claim 1, 2 or 3, in which the gear selector key is movable into axial abutment with a selector sleeve of the epicyclic change speed hub to effect axial displacement thereof. 5. An epicyclic change speed gear as claimed in claim 4, in which a clutch sleeve is provided internally of the selector sleeve and between the selector sleeve and hub spindle, the clutch sleeve being movable axially relative to the selector sleeve and there being resilient means between opposed formations on the clutch sleeve and selector sleeve, respectively, resisting movement of the clutch sleeve relative to the selector sleeve outwardly of the hub and a selector key displacing the selector sleeve outwardly of the hub through said resilient means. 6. An epicyclic change speed gear as claimed in claim 5, in which the clutch sleeve has a radially outwardly directed lip at its inner end and the selector sleeve has an internal rib, the lip being an interference fit with said rib, and the resilient means comprising a helical compression spring interposed therebetween. 7. A clutch for an epicyclic change speed gear comprising a clutch sleeve provided internally of the selector sleeve and between the selector sleeve and hub spindle, the clutch sleeve being movable axially relative to the selector sleeve and there being resilient means between opposed formations on the clutch sleeve and selector sleeve, respectively, resisting movement of the clutch sleeve relative to the selector sleeve outwardly of the hub and a selector key displacing the selector sleeve outwardly of the hub through said resilient means.

Inventors: RICKELS STEPHEN TERENCE, RICKELS, STEPHEN, TERENCE
Applicants: RICKELS STEPHEN TERENCE, STURMEY ARCHER LTD, RICKELS, STEPHEN, TERENCE, STURMEY-ARCHER LIMITED
Application year: 1994
Main classification: B62M11
IPC codes: B62M11, F16H3